diff --git a/web/api/v1/translate_ast.go b/web/api/v1/translate_ast.go
index b3f5eda212..dc2e7e2901 100644
--- a/web/api/v1/translate_ast.go
+++ b/web/api/v1/translate_ast.go
@@ -84,6 +84,8 @@ func translateAST(node parser.Expr) any {
 			"matchers":   translateMatchers(vs.LabelMatchers),
 			"timestamp":  vs.Timestamp,
 			"startOrEnd": getStartOrEnd(vs.StartOrEnd),
+			"anchored":   vs.Anchored,
+			"smoothed":   vs.Smoothed,
 		}
 	case *parser.SubqueryExpr:
 		return map[string]any{
@@ -124,6 +126,8 @@ func translateAST(node parser.Expr) any {
 			"matchers":   translateMatchers(n.LabelMatchers),
 			"timestamp":  n.Timestamp,
 			"startOrEnd": getStartOrEnd(n.StartOrEnd),
+			"anchored":   n.Anchored,
+			"smoothed":   n.Smoothed,
 		}
 	}
 	panic("unsupported node type")
diff --git a/web/ui/mantine-ui/src/pages/query/ExplainViews/Selector.tsx b/web/ui/mantine-ui/src/pages/query/ExplainViews/Selector.tsx
index ca575ca2f4..2c564d3a4a 100644
--- a/web/ui/mantine-ui/src/pages/query/ExplainViews/Selector.tsx
+++ b/web/ui/mantine-ui/src/pages/query/ExplainViews/Selector.tsx
@@ -171,9 +171,22 @@ const SelectorExplainView: FC<SelectorExplainViewProps> = ({ node }) => {
       <Text fz="sm">
         {node.type === nodeType.vectorSelector ? (
           <>
-            This node selects the latest (non-stale) sample value within the
-            last{" "}
-            <span className="promql-code promql-duration">{lookbackDelta}</span>
+            This node {node.smoothed ? "smooths the value" : "selects the latest"}{" "}
+            {node.anchored || node.smoothed ? "" : "non-stale "}
+            {!node.smoothed && (
+              <>
+                sample value within the last{" "}
+                <span className="promql-code promql-duration">{lookbackDelta}</span>
+              </>
+            )}
+            {node.smoothed && (
+              <>
+                using <code>smoothed</code> mode (linear interpolation with nearest
+                points within{" "}
+                <span className="promql-code promql-duration">{lookbackDelta}</span>{" "}
+                before and after execution timestamp, ignoring staleness markers)
+              </>
+            )}
           </>
         ) : (
           <>
@@ -182,6 +195,21 @@ const SelectorExplainView: FC<SelectorExplainViewProps> = ({ node }) => {
               {formatPrometheusDuration(node.range)}
             </span>{" "}
             of data going backward from the evaluation timestamp
+            {node.anchored && (
+              <>
+                {" "}
+                using <code>anchored</code> mode (includes first sample before or at
+                start boundary, and last sample of the range at end boundary, ignoring staleness markers)
+              </>
+            )}
+            {node.smoothed && (
+              <>
+                {" "}
+                using <code>smoothed</code> mode (applies linear
+                interpolation at the boundaries using nearest samples
+                before and after boundaries, ignoring staleness markers)
+              </>
+            )}
           </>
         )}
         {node.timestamp !== null ? (
diff --git a/web/ui/mantine-ui/src/pages/query/Graph.tsx b/web/ui/mantine-ui/src/pages/query/Graph.tsx
index bd92e28b23..a30d52c822 100644
--- a/web/ui/mantine-ui/src/pages/query/Graph.tsx
+++ b/web/ui/mantine-ui/src/pages/query/Graph.tsx
@@ -56,6 +56,8 @@ const Graph: FC<GraphProps> = ({
                 offset: node.offset,
                 timestamp: node.timestamp,
                 startOrEnd: node.startOrEnd,
+                anchored: node.anchored,
+                smoothed: node.smoothed,
               }
             : node
         );
diff --git a/web/ui/mantine-ui/src/pages/query/MetricsExplorer/LabelsExplorer.tsx b/web/ui/mantine-ui/src/pages/query/MetricsExplorer/LabelsExplorer.tsx
index d18c017b18..16b19ad9d3 100644
--- a/web/ui/mantine-ui/src/pages/query/MetricsExplorer/LabelsExplorer.tsx
+++ b/web/ui/mantine-ui/src/pages/query/MetricsExplorer/LabelsExplorer.tsx
@@ -94,6 +94,8 @@ const LabelsExplorer: FC<LabelsExplorerProps> = ({
     offset: 0,
     timestamp: null,
     startOrEnd: null,
+    anchored: false,
+    smoothed: false,
   };
 
   // Based on the selected pool (if any), load the list of targets.
diff --git a/web/ui/mantine-ui/src/pages/query/TreeNode.tsx b/web/ui/mantine-ui/src/pages/query/TreeNode.tsx
index 25ffdce650..b0ba1f68aa 100644
--- a/web/ui/mantine-ui/src/pages/query/TreeNode.tsx
+++ b/web/ui/mantine-ui/src/pages/query/TreeNode.tsx
@@ -130,12 +130,16 @@ const TreeNode: FC<{
   // more cheaply. E.g. 'foo[7w]' can be expensive to fully fetch, but wrapping it
   // in 'last_over_time(foo[7w])' is cheaper and also gives us all the info we
   // need (number of series and labels).
+  // Strip anchored/smoothed modifiers when wrapping, as last_over_time doesn't support them.
   let queryNode = node;
   if (queryNode.type === nodeType.matrixSelector) {
+    const matrixNode = { ...queryNode };
+    matrixNode.anchored = false;
+    matrixNode.smoothed = false;
     queryNode = {
       type: nodeType.call,
       func: functionSignatures["last_over_time"],
-      args: [node],
+      args: [matrixNode],
     };
   }
 
diff --git a/web/ui/mantine-ui/src/promql/ast.ts b/web/ui/mantine-ui/src/promql/ast.ts
index 3819c961b2..94872c6db0 100644
--- a/web/ui/mantine-ui/src/promql/ast.ts
+++ b/web/ui/mantine-ui/src/promql/ast.ts
@@ -147,6 +147,8 @@ export interface MatrixSelector {
   offset: number;
   timestamp: number | null;
   startOrEnd: StartOrEnd;
+  anchored: boolean;
+  smoothed: boolean;
 }
 
 export interface Subquery {
@@ -187,6 +189,8 @@ export interface VectorSelector {
   offset: number;
   timestamp: number | null;
   startOrEnd: StartOrEnd;
+  anchored: boolean;
+  smoothed: boolean;
 }
 
 export interface Placeholder {
diff --git a/web/ui/mantine-ui/src/promql/format.tsx b/web/ui/mantine-ui/src/promql/format.tsx
index 47cd259bd8..f4b883f678 100644
--- a/web/ui/mantine-ui/src/promql/format.tsx
+++ b/web/ui/mantine-ui/src/promql/format.tsx
@@ -131,6 +131,18 @@ const formatSelector = (
           ]
         </>
       )}
+      {node.anchored && (
+        <>
+          {" "}
+          <span className="promql-keyword">anchored</span>
+        </>
+      )}
+      {node.smoothed && (
+        <>
+          {" "}
+          <span className="promql-keyword">smoothed</span>
+        </>
+      )}
       {formatAtAndOffset(node.timestamp, node.startOrEnd, node.offset)}
     </>
   );
diff --git a/web/ui/mantine-ui/src/promql/serialize.ts b/web/ui/mantine-ui/src/promql/serialize.ts
index 1d2c63f4fc..bbccede708 100644
--- a/web/ui/mantine-ui/src/promql/serialize.ts
+++ b/web/ui/mantine-ui/src/promql/serialize.ts
@@ -56,13 +56,18 @@ const serializeSelector = (node: VectorSelector | MatrixSelector): string => {
     node.type === nodeType.matrixSelector
       ? `[${formatPrometheusDuration(node.range)}]`
       : "";
+  const extendedAttribute = node.anchored
+    ? " anchored"
+    : node.smoothed
+      ? " smoothed"
+      : "";
   const atAndOffset = serializeAtAndOffset(
     node.timestamp,
     node.startOrEnd,
     node.offset
   );
 
-  return `${!metricExtendedCharset ? metricName : ""}${matchers.length > 0 ? `{${matchers.join(",")}}` : ""}${range}${atAndOffset}`;
+  return `${!metricExtendedCharset ? metricName : ""}${matchers.length > 0 ? `{${matchers.join(",")}}` : ""}${range}${extendedAttribute}${atAndOffset}`;
 };
 
 const serializeNode = (
diff --git a/web/ui/mantine-ui/src/promql/serializeAndFormat.test.ts b/web/ui/mantine-ui/src/promql/serializeAndFormat.test.ts
index da4be7ced1..62b10cd781 100644
--- a/web/ui/mantine-ui/src/promql/serializeAndFormat.test.ts
+++ b/web/ui/mantine-ui/src/promql/serializeAndFormat.test.ts
@@ -24,6 +24,8 @@ describe("serializeNode and formatNode", () => {
           offset: 0,
           timestamp: null,
           startOrEnd: null,
+          anchored: false,
+          smoothed: false,
         },
         output: "metric_name",
       },
@@ -40,6 +42,8 @@ describe("serializeNode and formatNode", () => {
           offset: 0,
           timestamp: null,
           startOrEnd: null,
+          anchored: false,
+          smoothed: false,
         },
         output:
           'metric_name{label1="value1",label2!="value2",label3=~"value3",label4!~"value4"}',
@@ -52,6 +56,8 @@ describe("serializeNode and formatNode", () => {
           offset: 60000,
           timestamp: null,
           startOrEnd: null,
+          anchored: false,
+          smoothed: false,
         },
         output: "metric_name offset 1m",
       },
@@ -63,6 +69,8 @@ describe("serializeNode and formatNode", () => {
           offset: -60000,
           timestamp: null,
           startOrEnd: "start",
+          anchored: false,
+          smoothed: false,
         },
         output: "metric_name @ start() offset -1m",
       },
@@ -74,6 +82,8 @@ describe("serializeNode and formatNode", () => {
           offset: -60000,
           timestamp: null,
           startOrEnd: "end",
+          anchored: false,
+          smoothed: false,
         },
         output: "metric_name @ end() offset -1m",
       },
@@ -85,6 +95,8 @@ describe("serializeNode and formatNode", () => {
           offset: -60000,
           timestamp: 123000,
           startOrEnd: null,
+          anchored: false,
+          smoothed: false,
         },
         output: "metric_name @ 123.000 offset -1m",
       },
@@ -98,6 +110,8 @@ describe("serializeNode and formatNode", () => {
           offset: 60000,
           timestamp: null,
           startOrEnd: null,
+          anchored: false,
+          smoothed: false,
         },
         output: "metric_name offset 1m",
       },
@@ -110,6 +124,8 @@ describe("serializeNode and formatNode", () => {
           offset: 0,
           timestamp: null,
           startOrEnd: null,
+          anchored: false,
+          smoothed: false,
         },
         output: 'metric_name{label1="\\"\\"\\""}',
       },
@@ -129,6 +145,8 @@ describe("serializeNode and formatNode", () => {
           offset: 600000,
           timestamp: null,
           startOrEnd: null,
+          anchored: false,
+          smoothed: false,
         },
         output:
           'metric_name{label1="value1",label2!="value2",label3=~"value3",label4!~"value4"}[5m] offset 10m',
@@ -142,6 +160,8 @@ describe("serializeNode and formatNode", () => {
           offset: -600000,
           timestamp: 123000,
           startOrEnd: null,
+          anchored: false,
+          smoothed: false,
         },
         output: "metric_name[5m] @ 123.000 offset -10m",
       },
@@ -154,6 +174,8 @@ describe("serializeNode and formatNode", () => {
           offset: -600000,
           timestamp: null,
           startOrEnd: "start",
+          anchored: false,
+          smoothed: false,
         },
         output: "metric_name[5m] @ start() offset -10m",
       },
@@ -167,11 +189,164 @@ describe("serializeNode and formatNode", () => {
           offset: 0,
           timestamp: null,
           startOrEnd: null,
+          anchored: false,
+          smoothed: false,
         },
         output:
           '{label1="value1"}',
       },
 
+      // Anchored and smoothed modifiers.
+      {
+        node: {
+          type: nodeType.vectorSelector,
+          name: "metric_name",
+          matchers: [],
+          offset: 0,
+          timestamp: null,
+          startOrEnd: null,
+          anchored: true,
+          smoothed: false,
+        },
+        output: "metric_name anchored",
+      },
+      {
+        node: {
+          type: nodeType.vectorSelector,
+          name: "metric_name",
+          matchers: [],
+          offset: 0,
+          timestamp: null,
+          startOrEnd: null,
+          anchored: false,
+          smoothed: true,
+        },
+        output: "metric_name smoothed",
+      },
+      {
+        node: {
+          type: nodeType.vectorSelector,
+          name: "metric_name",
+          matchers: [],
+          offset: 60000,
+          timestamp: null,
+          startOrEnd: null,
+          anchored: true,
+          smoothed: false,
+        },
+        output: "metric_name anchored offset 1m",
+      },
+      {
+        node: {
+          type: nodeType.vectorSelector,
+          name: "metric_name",
+          matchers: [],
+          offset: 60000,
+          timestamp: null,
+          startOrEnd: null,
+          anchored: false,
+          smoothed: true,
+        },
+        output: "metric_name smoothed offset 1m",
+      },
+      {
+        node: {
+          type: nodeType.vectorSelector,
+          name: "metric_name",
+          matchers: [],
+          offset: 0,
+          timestamp: 123000,
+          startOrEnd: null,
+          anchored: true,
+          smoothed: false,
+        },
+        output: "metric_name anchored @ 123.000",
+      },
+      {
+        node: {
+          type: nodeType.matrixSelector,
+          name: "metric_name",
+          matchers: [],
+          range: 300000,
+          offset: 0,
+          timestamp: null,
+          startOrEnd: null,
+          anchored: true,
+          smoothed: false,
+        },
+        output: "metric_name[5m] anchored",
+      },
+      {
+        node: {
+          type: nodeType.matrixSelector,
+          name: "metric_name",
+          matchers: [],
+          range: 300000,
+          offset: 0,
+          timestamp: null,
+          startOrEnd: null,
+          anchored: false,
+          smoothed: true,
+        },
+        output: "metric_name[5m] smoothed",
+      },
+      {
+        node: {
+          type: nodeType.matrixSelector,
+          name: "metric_name",
+          matchers: [],
+          range: 300000,
+          offset: 600000,
+          timestamp: null,
+          startOrEnd: null,
+          anchored: true,
+          smoothed: false,
+        },
+        output: "metric_name[5m] anchored offset 10m",
+      },
+      {
+        node: {
+          type: nodeType.matrixSelector,
+          name: "metric_name",
+          matchers: [],
+          range: 300000,
+          offset: 600000,
+          timestamp: null,
+          startOrEnd: null,
+          anchored: false,
+          smoothed: true,
+        },
+        output: "metric_name[5m] smoothed offset 10m",
+      },
+      {
+        node: {
+          type: nodeType.matrixSelector,
+          name: "metric_name",
+          matchers: [],
+          range: 300000,
+          offset: 0,
+          timestamp: 123000,
+          startOrEnd: null,
+          anchored: true,
+          smoothed: false,
+        },
+        output: "metric_name[5m] anchored @ 123.000",
+      },
+      {
+        node: {
+          type: nodeType.matrixSelector,
+          name: "metric_name",
+          matchers: [],
+          range: 300000,
+          offset: 600000,
+          timestamp: 123000,
+          startOrEnd: null,
+          anchored: false,
+          smoothed: true,
+        },
+        output: "metric_name[5m] smoothed @ 123.000 offset 10m",
+      },
+
       // Aggregations.
       {
         node: {
@@ -309,6 +484,8 @@ describe("serializeNode and formatNode", () => {
                 offset: 0,
                 timestamp: null,
                 startOrEnd: null,
+                anchored: false,
+                smoothed: false,
               },
             ],
           },
@@ -681,6 +858,8 @@ describe("serializeNode and formatNode", () => {
                 startOrEnd: null,
                 timestamp: null,
                 type: nodeType.vectorSelector,
+                anchored: false,
+                smoothed: false,
               },
               grouping: ["a", "ä"],
               op: aggregationType.sum,
@@ -714,6 +893,8 @@ describe("serializeNode and formatNode", () => {
                 startOrEnd: null,
                 timestamp: null,
                 type: nodeType.vectorSelector,
+                anchored: false,
+                smoothed: false,
               },
               grouping: ["d", "ä"],
               op: aggregationType.sum,
@@ -744,6 +925,8 @@ describe("serializeNode and formatNode", () => {
               startOrEnd: null,
               timestamp: null,
               type: nodeType.vectorSelector,
+              anchored: false,
+              smoothed: false,
             },
             type: nodeType.parenExpr,
           },
diff --git a/web/ui/mantine-ui/src/promql/utils.test.ts b/web/ui/mantine-ui/src/promql/utils.test.ts
index 04e28a78f1..5166a6ffbf 100644
--- a/web/ui/mantine-ui/src/promql/utils.test.ts
+++ b/web/ui/mantine-ui/src/promql/utils.test.ts
@@ -118,6 +118,8 @@ describe("nodeValueType", () => {
           offset: 0,
           timestamp: null,
           startOrEnd: null,
+          anchored: false,
+          smoothed: false,
         },
         rhs: { type: nodeType.numberLiteral, val: "1" },
         matching: null,
@@ -138,6 +140,8 @@ describe("nodeValueType", () => {
           offset: 0,
           timestamp: null,
           startOrEnd: null,
+          anchored: false,
+          smoothed: false,
         },
         rhs: {
           type: nodeType.vectorSelector,
@@ -146,6 +150,8 @@ describe("nodeValueType", () => {
           offset: 0,
           timestamp: null,
           startOrEnd: null,
+          anchored: false,
+          smoothed: false,
         },
         matching: null,
         bool: false,